Recently, it has become popular to obtain tunes, such as musical songs, via the Internet, using mobile terminals such as mobile phones. Moreover, it is becoming popular to connect mobile terminals to in-vehicle audio devices. An example of such an in-vehicle audio device is proposed in Japanese Unexamined Patent Application Publication No. 2002-149165. In the in-vehicle audio device, desired tunes can be heard in a vehicle using an Internet function of a mobile terminal and tunes distributed via the Internet may be used as sound sources, without an expensive car audio device. According to Japanese Unexamined Patent Application Publication No. 2002-149165, a mobile terminal associated with the in-vehicle audio device can receive music data distributed via the Internet. Further, the in-vehicle audio device may include a display screen for displaying information associated with the received music data. Thus, in the in-vehicle audio device, tune titles, artist names, and the like can be displayed on the display screen.
Meanwhile, it is becoming popular to connect portable audio devices that have recently been in widespread use to in-vehicle audio devices. In general, portable audio devices include display units. Some portable audio devices receive an input of image data from in-vehicle audio devices and display the input image data on the display units when the portable audio devices are connected to the in-vehicle audio devices. Specifically, for example, a portable audio device is available, which performs such a display operation when the portable audio device is connected to an in-vehicle audio device with a universal serial bus (USB).
FIG. 7 illustrates a display state of a general in-vehicle audio device 100X and a general portable audio device 200 connected to each other with a USB. In the portable audio device 200, an image transmitted to the portable audio device 200 is displayed on the display unit 210 when the portable audio device 200 is connected to the in-vehicle audio device 100X with a USB. The display unit 210 may be a liquid crystal display (LCD). Thus, the in-vehicle audio device 100X can use the display unit 210 in the portable audio device 200, for example, in a manner in which the in-vehicle audio device 100X sends image data that includes a company's logo to the portable audio device 200.
To provide an inexpensive in-vehicle audio device, the in-vehicle audio device may include a segment display (for example, a fourteen-segment display or a sixteen-segment display). In general, in segment displays, although Arabic numerals, alphabets, and the like can be displayed, kanji characters, hiragana characters, and the like that are more complicated cannot be displayed because the expression is difficult. Thus, in the combination of the portable audio device 200 and the in-vehicle audio device 100X, tune titles, artist names, and the like that include kanji characters, kana characters, and the like cannot be displayed in both the portable audio device 200 and the in-vehicle audio device 100X while a tune is played back. In this case, in many cases, for example, a display such as “NO SUPPORT” as shown in FIG. 7 is presented in the in-vehicle audio device 100X.
Greater functionality has been achieved in in-vehicle audio devices, and users can perform a setting operation on various functions provided in in-vehicle audio devices. When such a setting operation is performed, in an in-vehicle audio device that includes a segment display, in many cases, settings on functions are displayed so that the settings are expressed in an abbreviated form, combining alphabets and Arabic numerals, because it is difficult to schematically express the settings. Since it is difficult to intuitively understand settings, seeing such a display, users are forced to perform a setting operation with reference to an instruction manual or intuitively on the basis of the results of operations until the users get accustomed to the display. Thus, an in-vehicle audio device that includes a segment display is less convenient for users in this respect, and useful functions may not be sufficiently effectively used due to such an inconvenience. Moreover, even in the case of an in-vehicle audio device that includes an LCD, when the size of the display unit is small, it has been difficult to schematically express settings on functions.